ERG4ALL
Posts: 603
Joined: Thu Sep 23, 2010 11:17 am
Delivery Date: 10 Mar 2011
Leaf Number: 000404
Location: Phoenix/Show Low AZ

Re: Weight of battery and cabin space

Sat May 18, 2013 7:54 am

Tony, I know you are right in stating that the LEAF's battery pack is 660 lbs. I don't know what the Tesla's pack weighs but you are a pretty thorough guy so I'm betting that 1,450 lbs. is correct. This brings up an interesting point. If the LEAF's battery pack were boosted up to the 85 kWh pack of the Tesla, then proportionately it would weigh 2,338 lbs. compared to Tesla's 1,450 lbs. I understand that Tesla uses over 18,000 cells. It is amazing to me that with all of that packaging, the Tesla would be so much lighter. Any thoughts?
Reserved 4/20/10, Ocean Blue Ordered SL 9/30/10, ESVE Installed 11/22/10, Delivered March 8th, 2011.

User avatar
TonyWilliams
Posts: 10091
Joined: Sat Feb 19, 2011 1:48 am
Location: San Diego
Contact: Website

Re: Weight of battery and cabin space

Sat May 18, 2013 8:31 am

Yogi62 wrote:roughly speaking, I've been equating a gallon of gas as 10 KW/h. The leaf has a "2 gallon" tank ... Could They have put another 6KW in the leaf by filling in part of the trunk or an extra layer of batteries in the floor, but the weight would be even worse. I could probably get by with a 12KW pack if I had reliable charging at work.
One gallon of gasoline is roughly equivalent to 33-35kWh. There are huge efficiency differences between the use of gas and electricity.

Yes, there have already been commercially available trunk mounted battery packs for the LEAF. I expect that Nissan will offer that as an option on future LEAFs.

User avatar
TonyWilliams
Posts: 10091
Joined: Sat Feb 19, 2011 1:48 am
Location: San Diego
Contact: Website

Re: Weight of battery and cabin space

Sat May 18, 2013 8:46 am

ERG4ALL wrote: It is amazing to me that with all of that packaging, the Tesla would be so much lighter. Any thoughts?
It's all in the chemistry and packaging. Nissan and GM went with a conservative chemistry with lower energy density per weight unit. Charles Whalen did a fantastic review in the Volt forum of they "whys". Basically, in his opinion, Nissan / GM and other large manufacturers can't afford to have a volatile chemistry that could be a risk to their entire company, but a start up like Tesla has nothing to lose. They have to take the risk to make the gains.

So far, it is paying off for Tesla. But, make no mistake; the risk is very real for bad things to happen. That is why Tesla has state-of-the-art battery packaging, temperature control, and battery management.

It's funny how little attention is paid to the risks with gasoline.

DanCar
Posts: 1042
Joined: Sat Apr 24, 2010 12:00 am
Delivery Date: 10 Mar 2013
Location: SF Bay area, 94043

Re: Weight of battery and cabin space

Sat May 18, 2013 12:44 pm

TonyWilliams wrote:..., but a start up like Tesla has nothing to lose. They have to take the risk to make the gains. ... Tesla has state-of-the-art battery packaging, temperature control, and battery management.
Tesla designed the battery packaging so that if one of the cells ignites it won't ignite all of the batteries.
TonyWilliams wrote:It's funny how little attention is paid to the risks with gasoline.
New technology is interesting where as old not so much. Although I would say that self ignition has higher chance with early EVs than gasoline cars. Take a look at Mitsubishi plug-in SUV and fiskar.
2013 Leaf SL leased 3/10/2013

Yogi62
Posts: 184
Joined: Sat Jan 12, 2013 7:29 pm
Delivery Date: 13 Apr 2013
Leaf Number: 405771
Location: Boston

Re: Weight of battery and cabin space

Sat May 18, 2013 2:55 pm

TonyWilliams wrote:
Yogi62 wrote:roughly speaking, I've been equating a gallon of gas as 10 KW/h. The leaf has a "2 gallon" tank ... Could They have put another 6KW in the leaf by filling in part of the trunk or an extra layer of batteries in the floor, but the weight would be even worse. I could probably get by with a 12KW pack if I had reliable charging at work.
One gallon of gasoline is roughly equivalent to 33-35kWh. There are huge efficiency differences between the use of gas and electricity.

Yes, there have already been commercially available trunk mounted battery packs for the LEAF. I expect that Nissan will offer that as an option on future LEAFs.
Yes, a gallon has 130,000,000 Joules, and a kwh is 3,600,000 which as you stated is about 35 to 1, but I was factoring in the low ICE efficiency. But logically, a gallon moves a good hybrid about 45-55 miles. The Leaf does the same with about 10 KW/h. 6.5 lbs and a cubic foot for gas, 300 lbs and many cubic feet for the battery.

The gas tank is so much smaller and lighter. The flip side is that the batteries can be spread out in more interesting shapes.

User avatar
Nubo
Posts: 5721
Joined: Fri May 28, 2010 11:01 am
Delivery Date: 31 Oct 2014
Location: Vallejo, CA

Re: Weight of battery and cabin space

Sat May 18, 2013 5:17 pm

TonyWilliams wrote:
Yogi62 wrote:roughly speaking, I've been equating a gallon of gas as 10 KW/h. The leaf has a "2 gallon" tank ... Could They have put another 6KW in the leaf by filling in part of the trunk or an extra layer of batteries in the floor, but the weight would be even worse. I could probably get by with a 12KW pack if I had reliable charging at work.
One gallon of gasoline is roughly equivalent to 33-35kWh. There are huge efficiency differences between the use of gas and electricity.
Yep. I like to tell folks that our LEAF has the equivalent of a 3-quart "tank". Thankfully we can get well over 100 miles per gallon. :)
I noticed you're still working with polymers.

Return to “Engineering”